PARIS, Nov 17 (Reuters) - France's former prime minister Alain Juppe is fighting an increasingly tight race to win the conservatives' nomination for next year's presidential election, an Ifop-Fiducial poll for Sud Radio showed on Thursday.

Juppe is seen getting 31 percent of votes in the first round of the primaries on Sunday, versus 30 percent for ex-president Nicolas Sarkozy and 27 percent for another former prime minister, Francois Fillon.

The poll was carried out online Nov 10-17 with 744 people certain to vote in the primaries. Juppe's rating is down 2 points since a survey carried out Oct 31-Nov 14, Sarkozy's unchanged and Fillon up 7 points.

Juppe would win the second round versus Sarkozy with 57 percent of the votes, the poll showed. (Reporting by Ingrid Melander; Editing by Andrew Callus)